TwinTurbo.NET: Nissan 300ZX forum - Re: Re: Re: Lets set a few things straight
People Seeking Info

Subject Re: Re: Re: Lets set a few things straight
Posted by Scott ZShack Taylor on September 14, 2017 at 1:53 PM
  This message has been viewed 339 times.
In Reply To Re: Re: Lets set a few things straight posted by Kyle(Houston) on September 13, 2017 at 09:29 PM
Message “I don't believe z1 ever claimed they were selling the ARP2000 bolts in their kits. I could be wrong though.”

Yes, they told me over the phone they where 2000’s Back when I first started purchasing them from them. Even if they didn’t, anyone looking at buying Studs may look at ARP’s website first and know that ARP only offers 1 head stud kit for the VG. This would lead a person to think they were buying 2000’s. This is a little deceitful at best.

“Yeah those are not the part numbers I use or have been using for at least 5-6 years now”

Care to share your part numbers? Pretty sure those part numbers are the only option for 8740 in our sizes. I could be wrong

“The 8740 have a longer thread depth and go into the block deeper then the ARP2000. In the picture you provided it certainly looks like they would be very close to the same height once seated into the block”

Yes they seat into the block a little further due to the undercut, but the installed height difference is 5.5mm. This means 5.5mm less useable threads.
Here are the measurements of properly installed ARP 8740 studs. This is the longer studs. I think we may be having a misunderstanding of my intent about this. I will try to explain. Over my years on Facebook and in person, I have seen numerous individuals rebuild a VG without a proper block cleaning. This coupled with not chasing the threads in the block has led to them installing the studs too shallow. When they installed them “finger tight”, they thought they fully seated them when they did not. As you will see in my diagram below, the 8740’s only have 7mm of wiggle room before the nut starts to lose threads. This is less with a decked block and head (obviously). With a thread pitch of 1.75mm the nut will get 1.75mm closer to running out of threads with each full turn.
While I know that an experienced person such as you and I would never have this issue, my write up was addressing the general public. I was simply trying to clarify how to install the studs properly and the differences between them. I even said in the write up that if you back the stud out too far it will run out of threads. I didn’t say it would if installed properly.

“Where is there a lack of thread engagement??? If you are claiming the top threads, I would like to see proof of that, please. Until then I will stand by my statements.”

Did you forget about the short bolts on the vg? You have to go off the torque specs of your weakest bolt. The short bolt has roughly 3 full turns less threads on it compared to the longer bolt. I assume since you sell parts you should have both in stock? Compare the threads between the short and long bolts and the difference in thread count. Or do I need to provide those measurements for you as well? Lol
this is why ARP lists the tq as less than what the longer bolt can handle. You say ARP2000 can go to 125, yet ARP lists in their instructions that you so adamantly like to reference, to tq their ARP2000 to 100FtLbs. So your claiming that you tq your 8740’s to more than what ARP says to tq their better 2000 bolts to? Maybe you know more than the manufacturer does about their parts? Also, please provide evidence of your TQ specs for the 8740’s. The whole reason we ended up calling them about it is because the information is not on the web.
Again I will tell you that ARP said absolutely do not go past 80 FtLbs on the VG with 8740. They have seen the treads roll at 83FtLbs. And also that if they have gone past 83FtLbs, then you have now torque to yield. Meaning do not reuse the bolts again. I’m sorry if you don’t like to hear this information but don’t shoot the messenger! You are welcome to contact them, tell them exactly what you are using and what you are torquing them to and see what they tell you. Ask for Al his ext is 204 when calling the main ARP number. He is a great guy with a ton of knowledge.

“Prove me wrong. The L19's and E85 builds have been being done now for probably 9-10 years. I have never heard of a L19 failure due to running E85. Until it becomes an issue or we can get 625+ studs for the VG30 platform; I will continue to recommend L19's for guys shooting over 650-700ish”

Maybe you should re read my write up. I expressly stated that this has not happened (yet). But why would you want to risk it? There is no need to run L19’s. Other platforms are running 2000 to more than double what we have ever made in the vg to date! Pretty much every engine builder and AL at ARP would tell you that if you are lifting a head with 2000’s then you are doing something wrong! Again in case you missed it, which it seems to be a common issue with you here. His extension is 204.

Try to follow the logic here, If you can TQ an L19 to 120, (which is likely higher than what ARP would say to go to on the VG) without issue, then you can tq ARP2000 to the same 120. They both have the same yield point of 125 FtLbs! What is good for one is good for the other! So why not use the 2000 that is not vulnerable to embrittlement? And yes you can get CA625+ custom made from ARP. So there is no reason to ever use L19! But unless you fix the issue of the smaller bolt on the VG, or go to a larger diameter stud, you will not benefit from the added tensile strength of 625+ anyway!

Direct quote from my write up…. “The ARP 2000 yield strength or the point in where the metal will stretch is 200,000 psi. L19 is 200,000 - 230,000 psi. Both will not reach yield until 125 Ft Lbs of torque or higher. The tensile strength or the point at which the bolt will break is higher on the L19, but both are still plenty high enough that if you ever broke one, it would be due to the engine operating out of an acceptable operating parameter! IE excessive head pressure or detonation etc.”
Again, both will place the same clamping force on the head. L19 will hold a little more before snapping but as I and many others have said before, if you are breaking a 2000 stud, you have way bigger issues than tensile strength!

Follow Ups  
Post a

You cannot reply to this message because you are not logged in.